text: /*
   * CDDL HEADER START
   *
   * The contents of this file are subject to the terms of the
   * Common Development and Distribution License, Version 1.0 only
   * (the "License").  You may not use this file except in compliance
   * with the License.
   *
   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   * or http://www.opensolaris.org/os/licensing.
   * See the License for the specific language governing permissions
   * and limitations under the License.
   *
   * When distributing Covered Code, include this CDDL HEADER in each
   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
   * If applicable, add the following below this CDDL HEADER, with the
   * fields enclosed by brackets "[]" replaced with your own identifying
   * information: Portions Copyright [yyyy] [name of copyright owner]
   *
   * CDDL HEADER END
   */
  /*
   * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  #pragma ident	"%Z%%M%	%I%	%E% SMI"
  
  /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
  /*	  All Rights Reserved  	*/
  
  
  /*
   * mesg -- set current tty to accept or
   *	forbid write permission.
   *
   *	mesg [-y | -n | y | n]
   *		y allow messages
   *		n forbid messages
   *	return codes
   *		0 if messages are ON or turned ON
   *		1 if messages are OFF or turned OFF
   *		2 if an error occurs
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <locale.h>
  #include <libintl.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  
  static void error(const char *s);
  static void newmode(mode_t m);
  static void usage(void);
  
  static char *tty;
  
  int
  main(int argc, char *argv[])
  {
  	int i, c, r = 0;
  	int action = 0;
  	struct stat sbuf;
  
  	extern int optind;
  
  	(void) setlocale(LC_ALL, "");
  #if !defined(TEXT_DOMAIN)		/* Should be defined by cc -D */
  #define	TEXT_DOMAIN	"SYS_TEST"	/* Use this only if it weren't */
  #endif
  	(void) textdomain(TEXT_DOMAIN);
  
  	/*
  	 * Check stdin, stdout and stderr, in order, for a tty
  	 */
  	for (i = 0; i <= 2; i++) {
  		if ((tty = ttyname(i)) != NULL)
  			break;
  	}
  
  	if (stat(tty, &sbuf) < 0)
  		error("cannot stat");
  
  	if (argc < 2) {
  		if (sbuf.st_mode & (S_IWGRP | S_IWOTH)) {
  			(void) printf("is y\n");
  		} else {
  			r = 1;
  			(void) printf("is n\n");
  		}
  		exit(r);
  	}
  
  	while ((c = getopt(argc, argv, "yn")) != EOF) {
  		switch (c) {
  		case 'y':
  			if (action > 0)
  				usage();
  
  			newmode(S_IRUSR | S_IWUSR | S_IWGRP);
  			action++;
  			break;
  
  		case 'n':
  			if (action > 0)
  				usage();
  
  			newmode(S_IRUSR | S_IWUSR);
  			r = 1;
  			action++;
  			break;
  
  		case '?':
  			usage();
  			break;
  		}
  	}
  
  	/*
  	 * Required for POSIX.2
  	 */
  	if (argc > optind) {
  		if (action > 0)
  			usage();
  
  		switch (*argv[optind]) {
  		case 'y':
  			newmode(S_IRUSR | S_IWUSR | S_IWGRP);
  			break;
  
  		case 'n':
  			newmode(S_IRUSR | S_IWUSR);
  			r = 1;
  			break;
  
  		default:
  			usage();
  			break;
  		}
  	}
  
  	return (r);
  }
  
  void
  error(const char *s)
  {
  	(void) fprintf(stderr, "mesg: ");
  	(void) fprintf(stderr, "%s\n", s);
  	exit(2);
  }
  
  void
  newmode(mode_t m)
  {
  	if (chmod(tty, m) < 0)
  		error("cannot change mode");
  }
  
  void
  usage(void)
  {
  	(void) fprintf(stderr, gettext("usage: mesg [-y | -n | y | n]\n"));
  	exit(2);
  }
  